中国青島産コノハクラゲ(ヒドロ虫綱, 軟クラゲ目)の生活環と型の決定

Abstract

In September 2007, hydroids of Eutima japonica Uchida, a bivalve-inhabiting hydrozoan, were found for the first time in Tsingtao, China, associating with Mytilus galloprovincialis (23.5% prevalence, N=230), and their mature medusae were obtained by culture for 6.5 months in the laboratory (9 hosts kept). The morphology of both hydroids and medusae of this species, appeared as the southern Japanese form (demonstrated by 30 mature medusae of both sexes), is descnbed with photographs illustrating for the first time the connection between the two developmental stages for the Chinese materials.

2007年9月に中国の青島の磯浜で採取した230個体のムラサキイガイMytilus galloprovincialis からカイヤドリヒドラ類のポリプを発見し(共生率23.5%), 実験室での6.5ヶ月にわたる9個体の福主の飼育により, それより遊離した未成熟クラゲから成熟した雌雄のコノバクラゲEutima japonica Uchidaの計30個体が得られた. それらの形態の精査の結果, 傘縁に多数の糸状体(最多232本)をもつ大形(最大傘径13mm)の南日本型のコノバクラゲであると決定できたので,ポリプとクラゲの形態を写真も含めて記載する.